This invention relates to an airbag system.
Airbag restraint systems in the area of the pelvis or upper torso of the occupant are known. With these known systems, airbags are set in a belt or the seat belt is formed as an airbag.
Thus from German patent DE 43 06 528 A1, an airbag for seat belts is known wherein an airbag pocket is fitted on the existing belt and is connected to a compressed air line, as well as to a compressed air generator and release unit.
Furthermore an inflatable seat belt unit is known from German patent DE 42 32 041 A1 wherein at least one part of a section, which is in contact with an occupant in a vehicle, is formed in a bag-like form. The bag-like section thereby retains a belt-like shape in the inactivated state and in the event of a crash is inflated and unfolded by the gas. With this seat belt unit the seat belt is thus, itself, formed in sections as an airbag.
The advantage of these belt airbags is that as opposed to airbags which are stowed on the steering wheel or on parts of the vehicle bodywork located in front of the occupant, the belt airbags are placed directly against the occupant, i.e., they are already located in the area in which they are to exert their protective effect.
The drawback with these belt airbags however is that the airbag fabric is moved when putting the belt on and off so that it is exposed to changing stresses. The danger here is that the fabric wears away without the gas bag being unfolded.
The object of the invention is, therefore, to substantially avoid, in the case of an airbag system which can also be used in connection with a seat belt, the movement of the gas bag in the inactivated state.
With an airbag system having a gas bag and a gas generator according to the invention, at least one flexible guideway is provided which is connected fixedly at one end to the motor vehicle and detachably at the other end to the motor vehicle, wherein the gas bag in the inactivated state is mounted on the fixedly connected end of the guideway and wherein the gas bag after ignition of the gas generator can be moved along the guideway in the direction of the other detachable end under the influence of the gases entering into the gas bag.
The advantage of this airbag system is that the gas bag provided at the end of the flexible guideway connected fixed to the motor vehicle is not or is hardly moved during releasing and fixing of the other end of the guideway, and that the gas bag material is not exposed to any changing stresses. The gas bag is thereby located with this airbag system according to the invention in the inactivate state outside of the position required for protecting the occupant. Only after ignition of the gas generator is it brought into the position required to protect the occupant.
In one embodiment at least one guide element which is automatically guided on the guideway is provided on the gas bag. It is expedient if at least one shackle or ring is used as the guide element and where several guide elements are used these are arranged at a distance from each other. With this embodiment the guide elements engage around the guideway. The guide elements cause the gas bag to be automatically guided to the other end of the guideway after ignition of the gas generator.
It is expedient if the gas bag has a tubular gas inlet whose length is measured so that it is fully stretched in the fully unfolded state of the gas bag when the belt is fully extended and forms a slack when the belt is less extended. As a result of this different stretching of the gas inlet in dependence on the build of the occupant the gas bag is automatically centered on the guideway as it is unfolded independently of the extension length of the belt and thus of the guideway.
In a further development, it is proposed that the gas bag has a separate chamber running in the inflated state of the gas bag substantially parallel to the guideway and stretching from the gas generator side out over practically the entire width of the gas bag. It is thereby expedient if the chamber is divided by a rip seam or by a sewn-in intermediate wall from the remaining area of the gas bag. The gas bag is then first inflated in the separate chamber whereby the gas bag prior to full inflation is brought into the position required for protecting the occupant. The gas then enters into the remaining area of the gas bag through at least one port which is either already present or which is formed by tearing open and/or after the rip seams have torn open the gas enters over the entire width into the remaining area as a result of the gas bag interior which is now in one uniform piece.
The guideway can extend in the area of the occupant in different ways. Thus it can extend in front of the occupant from one seat side to the other whereby the gas generator is mounted at the side of the seat or behind same and wherein the gas bag is mounted in the inactivated state at the side of the seat and after ignition of the gas generator can be moved in the direction of the other side of the seat. With this arrangement a belt is preferably provided as the guideway which can be formed both as a seat belt lying taut against the occupant and as a belt lying loose against the occupant.
In a preferred embodiment, the section of a 3-point automatic belt mechanism running in the pelvic area is provided as the guideway.
In a further embodiment the belt or belt section running in the pelvic area is formed in two layers whereby only the second layer fixed on the first layer is provided as the guideway for the unfolding gas bag. The length of the guideway is dimensioned between its two connecting points on the first layer so that a predetermined distance can be set between the lap belt or lap belt section of a 3-point automatic belt mechanism closely adjoining the occupant, and the guideway during unfolding of the gas bag.
The twin-layered design can be used not only in the lap area but also in the shoulder area.
The belt can be placed like a standard seat belt and when not in use can hang by its detachable end from one side of the vehicle.
In one design it is proposed that the belt runs from the side on which the gas bag is mounted with the gas generator, out from a belt mechanism to the opposite side of the occupant where it is deflected and guided movable in a guide provided with a belt lock and then runs back to the other side to a belt mounting in the area of the gas generator.
In order to reliably prevent the relaxing gas bag from running back it is expedient if a non-return lock is provided on the gas bag to interact with the guideway. This has in one embodiment two cylindrical locking members mounted movable in a guide and set opposite one another on different sides of the guideway.
In a further embodiment it is proposed to use the airbag system according to the invention also for a side airbag. In this case the guideway extends at the side behind the occupant from the floor area to the head area. The gas generator and the inactivated gas bag are then mounted preferably in the floor area. The section of a 3-point automatic belt mechanism running between the belt automatic unit and the upper deflection is preferably provided as the guideway.
The airbag system can be used not only in passenger vehicles but also in all other types of motor vehicles.